Police found a woman dead
in her study. She was
slumped over her desk with a gun in her hand. A cassette
recorder was on her desk. When the
police entered the study, they pressed the play button on the tape
recorder.The
police heard: “I can’t go on. I have
nothing to live for.” Then there
was the sound of a gunshot.

Question :
How did the police know that the woman had been murdered, that it
wasn’t a suicide?